: A few years back I visited West Systems and talked to one of the Gougeon bothers.
: He told me they had done research on wetting out one layer and two layers of glass cloth.
: They found that wetting out more than one layer (without vacuum bagging) at a time, caused
: excess resin to be absorbed resulting in excess weight. They recommend wetting out single layers : where excess resin is squeegeed off.
: Follow this link to see the methods I suggest to get a consistantly transparent lay-up.
: Rob

I think you have answered a different question: how to achieve a super-clear layup over wood with typically one or two layers of glass. I was addressing a broader question of monolithic Vs non-monolithic layups. Suppose I'm building something with six layers; the thought of doing six single-layer layups separated by hours of waiting, de-blushing, de-glossing, and roughening... instead of one monolithic layer, is not good. The way to achieve the highest cloth-to-resin ratio is to do it all at once: laying, squeegeeing, brushing, and bubble-rolling each layer individually in rapid succession. You could vacuum bag it too, to remove a little more resin. A different technique: placing all layers DRY, then wetting through ALL layers in one shot, should be vacuum bagged, and is what (I think.) the Gougeon bros were referring to.

If you hit each layer of fabric with your finned roller, you will eliminate the waviness of the cloth over resin puddles and air pockets, by eliminating them. This will also tend to prevent the first layer from sliding around as you lay out the second layer of fabric.

I have verified the cloth-to-resin ratios using disks of laminate cut from actual boats... another reason to put a clear window in the cockpit floor. If you cut a perfect hole with a hole saw, you can easily calculate the area of your disk... you will need a small but accurate scale, too.

My main comment on the instructions you linked to was the lack of mentioning a bubble roller (aka: ringed roller, bubble-buster roller, finned roller). For everyone who has not used an aluminum finned roller, you are in for an awakening... it is the disgronifier of FRP tools. That's (F)iber (R)einforced (P)lastic. The ringed roller de-floats the cloth, pushing it down against whatever you are covering, without plowing the resin around, and without shoving the cloth around. Just for fun, lay up a piece of glass on a sheet of aluminum foil on a board without using a ringed roller, getting the resin just right. Now hit it with a ringed roller and see that extra resin that you didn't realize you were using. Throw a dry piece of glass on top; you will discover how much extra resin you have been using... maybe enough to saturate a second layer of glass. The quality of your work just went way up!

Clean the finned roller with vinegar before the epoxy hardens. I prefer the aluminum ones, not the plastic. You can clean an aluminum roller with a torch if you don't hit it with vinegar in time. The flaming epoxy stink is amazing, so wait for a windy day!

I use WEST resin, too. I have NEVER had a problem with it. I de-blush with warm water and dish detergent, NOT SANDPAPER!

I don't use acetone, nor any other dangerous solvent. Vinegar is cheap and safe and works great.